Methods of injection molding an article

ABSTRACT

Embodiments of the invention relate to injection mold components, assemblies, and molding system that include superhard materials. Such injection mold components, assemblies, and systems may decrease wear of certain injection mold components, which may result in improved productivity of the injection mold and molding systems that utilize such components.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/463,471 filed on 3 May 2012, which is a continuation-in-part of U.S.patent application Ser. No. 13/005,212 filed on 12 Jan. 2011 (now U.S.Pat. No. 8,512,023 issued on 20 Aug. 2013), the disclosure of each ofwhich is incorporated herein, in its entirety, by this reference.

BACKGROUND

Injection molding processes have relatively widespread use and may beemployed to produce a wide variety of parts. For instance, injectionmolded parts may range from only a few millimeters in size to parts thatare several meters wide. Injection molding also may be used producecomponents that have various geometries, complexity of which may varyfrom simple to highly intricate in detail. Furthermore, injectionmolding processes may produce parts from various materials, includingbut not limited to thermoplastic polymers, aluminum alloys, zinc alloys,etc.

Oftentimes, molds used to manufacture injection molded parts (i.e.,injection molds) may be relatively expensive. Consequently, injectionmolding is most commonly used to manufacture parts in large quantities.This may allow the cost of the injection mold to be amortized overthousands or even hundreds of thousands of molded parts.

Typical molds are constructed from metallic materials, such as steel,aluminum, brass, copper, etc. Usability of the mold may vary based onthe materials used therein. For example, use of softer and/or lesswear-resistant metals, which may exhibit increased wear in an injectionmold, may lead to unusable parts produced by the mold. Ordinarily,material wear results from “cycling” the mold—i.e., closing the mold,injecting molten molding material, opening the mold, and/or ejecting orremoving the parts. The rate and/or amount of wear may depend on thepart geometry, molding material used in the process, frequency andnumber of cycles, and other factors present during the operation of themold.

Additionally, an injection mold may include certain components that mayexhibit more wear than other components, due to the nature of theoperation of the mold. Thus, in some instances, a typical mold mayrequire repair or replacement where increased wear may lead to failureof such components.

SUMMARY

Various embodiments of the invention are directed to injection moldassemblies and components that comprise a superhard material, as well asinjection molding system that may utilize such injection mold assembliesand components. Superhard materials may be arranged and formed in anynumber of sizes and configurations. In some embodiments, superhardmaterials may be available in limited sizes. Hence, multiple segmentsmay be used to enable forming desired surface sizes and configurations,notwithstanding possible limitations in the size of available superhardmaterials. Superhard materials also may be located along all or portionof one or more surfaces of the injection mold component, to form one ormore wear-resistant surface, which may provide increased resistance towear for such surfaces of the injection mold component.

According to one embodiment, an injection mold component for use in aninjection mold includes a substrate and a superhard material bonded tothe substrate that forms a wear-resistant surface. The wear-resistantsurface is moveable within the injection mold, and/or the wear-resistantsurface defines at least a portion of a conduit for communicating amolding material flows into the injection mold.

According to another embodiment, an injection mold assembly includes afirst mold plate, a second mold plate, and one or more molding elementslocated on one or more of the first or second mold plates. The injectionmold assembly also includes an injection mold component located on atleast one of the first mold plate, on the second mold plate, or on themolding element. The injection mold component includes a superhardmaterial forming at least a portion of a surface of the injection moldcomponent, wherein the superhard material is bonded to a substrate.

According to yet another embodiment, an injection molding systemincludes an injection molding machine and an injection mold operablycoupled to the injection molding machine. The injection mold includes astationary portion, a moving portion, and one or more molding elementslocated on the stationary and/or on the moving portions. The injectionmold also includes an injection mold component located on the stationaryportion and/or on the moving portion. The injection mold componentincludes a superhard material forming a wear-resistant surface on theinjection mold component. The superhard material is bonded to asubstrate. The injection molding machine is configured to move themoving portion. The injection molding machine is also configured toinject molding material into the injection mold via a conduit at leastpartially defined by the wear-resistant surface of the injection moldcomponent; or the wear-resistant surface is moveable within theinjection mold.

Features from any of the disclosed embodiments may be used incombination with one another, without limitation. In addition, otherfeatures and advantages of the present disclosure will become apparentto those of ordinary skill in the art through consideration of thefollowing detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate several embodiments of the invention, whereinidentical reference numerals refer to identical or similar elements orfeatures in different views or embodiments shown in the drawings.

FIG. 1 is a schematic cross-sectional view of an injection moldingmachine and an injection mold, which may utilize any of the injectionmold components disclosed herein;

FIG. 2 is a cross-sectional view of an injection mold in accordance withone embodiment of the invention;

FIG. 3A is a cross-sectional view of sprue bushing of an injection moldin accordance with one embodiment of the invention;

FIG. 3B is a cross-sectional view of a sprue bushing of an injectionmold in accordance with another embodiment of the invention;

FIG. 3C is a cross-sectional view of a sprue bushing of an injectionmold in accordance with yet another embodiment of the invention;

FIG. 3D is a cross-sectional view of a hot runner system and various hottips in accordance with one embodiment of the invention;

FIG. 3E is a cross-sectional view of a gate insert of an injection moldin accordance with one embodiment of the invention;

FIG. 4A is a cross-sectional view of a locating ring of an injectionmold in accordance with one embodiment of the invention;

FIG. 4B is a cross-sectional view of a locating ring of an injectionmold in accordance with another embodiment of the invention;

FIG. 5A is a cross-sectional view of an ejector sleeve of an injectionmold in accordance with one embodiment of the invention;

FIG. 5B is a cross-sectional view of an ejector sleeve of an injectionmold in accordance with another embodiment of the invention;

FIG. 5C is a cross-sectional view of an ejector sleeve of an injectionmold in accordance with yet another embodiment of the invention;

FIG. 5D is a cross-sectional view of a different embodiment of anejector sleeve of an injection mold in accordance with one embodiment ofthe invention;

FIG. 5E is a cross-sectional view of yet another embodiment of anejector sleeve of an injection mold in accordance with one embodiment ofthe invention;

FIG. 6A is a cross-sectional view of an undercut relief system of aninjection mold in accordance with one embodiment of the invention;

FIG. 6B is a cross-sectional view of the undercut relief system of FIG.6A taken along line 6B-6B thereof;

FIG. 6C is a cross-sectional view of an undercut relief system of aninjection mold in accordance with another embodiment of the invention;

FIG. 6D is a cross-sectional view of an undercut relief system of aninjection mold in accordance with yet another embodiment of theinvention;

FIG. 6E is a cross-sectional view of an undercut relief system of aninjection mold in accordance with another embodiment of the invention;

FIG. 6F is an isometric view of an undercut relief system of aninjection mold in accordance with yet another embodiment of theinvention;

FIG. 6G is an isometric view of an undercut relief system of aninjection mold in accordance with yet another embodiment of theinvention;

FIG. 7A is a cross-sectional view of a slide retainer in accordance withone embodiment of the invention;

FIG. 7B is a cross-sectional view of a slide retainer in accordance withanother embodiment of the invention;

FIG. 8A is an isometric view of a rectangular two-plate interlock pairin an open position in accordance with one embodiment of this invention;

FIG. 8B is an isometric view of a rectangular two-plate interlock pairin a closed position in accordance with another embodiment of thisinvention;

FIG. 8C is a side view of a three-plate interlock pair in an openposition in accordance with one embodiment of this invention;

FIG. 8D is a side view of a three-plate interlock pair in a partiallyclosed position in accordance with another embodiment of this invention;

FIG. 8E is an isometric view of a tapered interlock pair in accordancewith one embodiment of this invention;

FIG. 8F is a side view of a tapered interlock pair in a closed positionin accordance with another embodiment of this invention;

FIG. 8G is an isometric view of a cylindrical tapered interlock pair inaccordance with one embodiment of this invention; and

FIG. 8H is a cross-sectional view of a cylindrical tapered interlockpair in a closed position in accordance with another embodiment of thisinvention.

DETAILED DESCRIPTION

Various embodiments of the invention are directed to injection moldassemblies and components that comprise a superhard material, as well asinjection molding system that may utilize such injection mold assembliesand components. Superhard materials may be arranged and formed in anynumber of sizes and configurations. In some embodiments, superhardmaterials may be available in limited sizes. Hence, multiple segmentsmay be used to enable forming desired surface sizes and configurations,notwithstanding possible limitations in the size of available superhardmaterials. Superhard materials also may be located along all or portionof one or more surfaces of the injection mold component, to form one ormore wear-resistant surface, which may provide increased resistance towear for such surfaces of the injection mold component.

There are numerous types of injection molding machines and techniquesavailable for manufacturing injection molded parts. In particular, theinjection molding machine may inject, for example, moltenthermoplastics, thermosets, elastomers, aluminum alloys, and zinc alloysinto an injection mold, to manufacture various parts from such materialsor combinations thereof. Additionally, the injection molding machine mayinject thermoplastics, thermosets, elastomers, or combinations thereofthat incorporate metallic powder, thereby producing a “green” part,which may allow the manufacturer to make metal parts by removing thepolymer material from the “green part” and sintering the metallicpowder. FIG. 1 illustrates an injection molding system 100, which mayinclude an injection molding machine 110 and an injection mold 120(shown in a closed position). Although the particular configuration oroperation of the injection molding machine 110 may vary in some regardswith respect to other available machines or processes, the injectionmolding machine 110 may be a typical machine used for manufacturinginjection molded parts.

The injection molding machine 110 may include a front platen 111 and aback platen 112. The back platen 112 may move with respect to the frontplaten 111, which may cause the injection mold 120 to open. Inparticular, the injection mold 120 may have a stationary portion 121 anda moving portion 122, which may define a parting line 123 (i.e., theline (or one or more planes) along which the injection mold 120 splitsto open). The stationary portion 121 of the injection mold 120 may besecured to the front platen 111 and the moving portion 122 may besecured to the back platen 112. Accordingly, movement of the back platen112 in a direction away from the front platen 111 may cause the movingportion 122 of the injection mold 120 to move away from the stationaryportion 121, thereby opening the injection mold 120 along the partingline 123. Similarly, movement of the back platen 112 toward the frontplaten 111 may cause the injection mold 120 to close.

The injection molding machine 110 also may include a material hopper 113and an injection system 114, which may supply molten molding materialinto the injection mold 120. More particularly, molding material (e.g.,plastic pellets) may be added into the material hopper 113 and fed intothe injection system 114. In one embodiment, the injection system 114may include a screw 115 that may rotate within a barrel. Optionally, oneor more heaters 116 may surround the barrel to heat and/or at leastpartially or completely melt the molding material.

The melted molding material may be conveyed by the screw 115, which maybe a reciprocating screw, toward the injection mold 120. The moltenmolding material may be injected into the injection mold 120 through aninjection nozzle 117. It should be noted that other configurations ofthe injection molding machine 110 may be used to manufacture moldedparts. For instance, the injection system 114 may include a plunger,which may replace or may be incorporated into the screw 115, and whichmay inject the molten molding material into the injection mold 120.

Once the injection mold 120 is in a fully closed position (as shown inFIG. 1), molten molding material may be injected into the injection mold120. More specifically, the molten material may fill a molding volume131 within the injection mold 120. Subsequently, as shown in FIG. 2, themolten molding material may cool and at least partially solidify to forma part corresponding to the molding volume 131. When the molten moldingmaterial forming the part has cooled to a desired temperature, theinjection mold 120 may be opened, by moving the back platen 112 awayfrom the front platen 111 (as described above), and the part may beejected or removed from the injection mold 120.

To produce the part, the injection mold 120 may incorporate variousmolding elements, which may have necessary shapes and sizes to form apart 130. For example, as illustrated in FIG. 2, the injection mold 120may include one or more molding elements 140, such as molding elements140 a, 140 b, 140 c (which may include a cavity, a core, a core pin,core inserts, etc.) that assemble to define the molding volume 131. A“molding element” refers to any portion of the injection mold 120 thatforms at least a portion of the part 130 (i.e., portion(s) of theinjection mold 120 that define the molding volume 131). Thus, to producemultiple parts in a single cycle, the injection mold 120 may includemultiple sets of molding elements 140, which may be substantiallyidentical (to produce the same parts) or may vary, for production ofdifferent parts in the single cycle. A “set of molding elements” refersto the molding elements 140 that, when combined, form or define themolding volume 131 (see FIG. 1), which may accept molten material andform the part 130.

As described above, the injection mold 120 may be secured in theinjection molding machine 110. More specifically, the injection mold 120may be secured to the front platen 111 and back platen 112. Forinstance, the nonmoving portion 121 of the injection mold 120 may haveone or more clamping grooves that may accommodate clamps for securingthe nonmoving portion 121 to the front platen 111 of the injectionmolding machine 110. For example, the nonmoving portion 121 may includeone or more plates, such as a first plate 121 a and a top clamping plate121 b, which may form such clamping grooves. The nonmoving portion 121also may include an overhang that may accommodate clamps, bolt holesthat may accept bolts for securing the nonmoving portion 121 to thefront platen 111, and/or other features that may be used to secure thenonmoving portion 121 to the front platen 111, which should beappreciated by those skilled in the art.

The nonmoving portion 121 also may include a sprue bushing 150, whichmay channel the molten molding material into the injection mold 120. Forexample, the injection nozzle 117 may have a spherical tip which maycontact a sphere of the same or similar radius on the sprue bushing 150.Subsequently, the molten molding material may flow from the injectionsystem 114 of the injection molding machine 110, through the injectionnozzle 117, through the sprue bushing 150, and into the injection mold120. In some instances, the nonmoving portion 121 also may include alocating ring 160, which may aid in aligning the injection mold 120and/or the sprue bushing 150 with the injection molding machine 110 aswell as with the injection nozzle 117.

The moving portion 122 of the injection mold 120 may be connected to theback platen 112 of the injection molding machine 110. Similar to thenonmoving portion 121, the moving portion 122 may incorporate a clampinggroove or other features that may allow the manufacturer to connect themoving portion 122 of the injection mold 120 to the back platen 112 ofthe injection molding machine 110. Furthermore, the moving portion 122may include a second plate 122 a that may secure or incorporate themolding element 140 b. The moving portion 122 of the injection mold 120also may include a support plate 122 b, which may provide support to thesecond plate 122 a and additional rigidity to the injection mold 120.

Additionally, the moving portion 122 and the nonmoving portion 121 ofthe injection mold 120 may include leader pins and correspondingbushings (not shown), which may aid in aligning the moving portion 122and the nonmoving portion 121 during the opening and closing of theinjection mold 120. In some embodiments, it may be desirable to provideadditional alignment mechanisms, to further align the moving and thenonmoving portions 122, 121 of the injection mold 120 as well as toprevent undesirable movement of the nonmoving and moving portions 121,122 during injection of the molding material. For example, as furtherdescribed below, the injection mold 120 may include interlock pairs 280,which may comprise male and corresponding female interlock portions.Furthermore, clearance between the male and the corresponding femaleinterlock portions may be substantially smaller than the clearancebetween the leader pins and corresponding bushings. For instance, theclearance between the male and female interlocks may be in the range of0.0002 inch to 0.0005 inch per side.

The injection mold 120 also may incorporate an ejection mechanism, whichmay eject the part 130 after the part 130 has cooled down to a desiredtemperature. In particular, the ejection mechanism may include anejector housing 122 c and ejector plates 122 d. For example, the ejectorplates 122 d may connect to an ejection system of the injection moldingmachine 110, which may move the ejector plates 122 d toward the frontplaten 111. The ejector plates 122 d, in turn, may secure one or moreejector pins 170, which may move together with the ejector plates 122 dand eject the part 130 out of the injection mold 120.

In some embodiments, as further described below, the injection mold 120also may incorporate one or more ejector sleeves, such as ejectorsleeves 220 a, 220 b. More particularly, the ejector sleeve 220 a mayguide the ejector pin 170 through the molding element 140 b. Hence, aportion (e.g., a top surface) of the ejector sleeve 220 a may contactthe part 130 and may at least in part form the molding volume 131.

In at least one embodiment, a core pin 140 c may be secured in theejector housing 122 c. The core pin 140 c may at least in part definethe molding volume 131 (e.g., the core pin 140 c may form a hole in thepart 130). The ejector sleeve 122 b may provide additional uniformityduring ejection of the part 130. More specifically, the ejector plates122 d also may secure one or more ejector sleeves, such as the ejectorsleeve 122 b, which may slide about the core pin 140 b, thereby aidingin ejection of the part 130.

It should be appreciated that the injection mold 120 may include all,some, and/or additional molding elements, plates, and/or devicesdescribed herein. For instance, the injection mold 120 may have noejector housing or ejector plates, and the manufacturer may choose toremove the parts with a robotic arm (or manually) to avoid ejector pinmarks on the parts. Additionally or alternatively, the injection mold120 may also include additional plates and/or devices, not describedherein, which may be necessary for operation. For example, in lieu ofejector pins, the manufacturer may choose to use a stripper plate (whereapplicable), which may strip the part 130 from the molding element 140b. Thus, it should be noted that components described herein may be usedin the injection mold 120 of any configuration or design.

In some instances, the part 130 may include undercuts or undercuttingportions, which may need to be relieved before the part 130 may beejected from the injection mold 120. In particular, one or more slidesor lifters may be used to relieve undercuts and allow the part 130 to beejected, as described in more detail below. A slide may movesubstantially orthogonally with respect to the undercut, therebyremoving at least a portion of the molding element 140 away from thepart 130. A lifter may move in a direction of ejection (i.e., toward thefront platen 111) and orthogonally to the undercut—thus, ejecting thepart while relieving the undercut.

In at least one embodiment, one or more surfaces of one or morecomponents comprising the injection mold 120 may include one or morelayers of superhard material. More particularly, one or more layers ofsuperhard material may form one or more wear-resistant surfaces on theinjection mold components. An “injection mold component” refers to anycomponent and/or element comprising an injection mold. Also, as usedherein, the term “superhard,” or the phrase “superhard material,” refersto any material having a hardness that is at least equal to the hardnessof tungsten carbide. Furthermore, element numbers denoted with letters“sm” identify superhard material in particular embodiments. It should benoted that so denoted superhard material may be any superhard materialdisclosed herein. Similarly, element numbers denoted with letters “wr”identify wear-resistant surface that may be formed by one or more layersof superhard material on a particular injection mold component.

In some embodiments, one or more substrates may be bonded to theinjection mold components. The substrates may be a cobalt-cementedtungsten carbide substrate or other carbide substrate. Additionally, thelayer of superhard material forming the wear-resistant surface may benatural diamond, polycrystalline diamond, polycrystalline cubic boronnitride, silicon carbide, diamond grains bonded together with siliconcarbide, or any combination of the preceding materials. Furthermore, thesuperhard material may be thermally-stable diamond in which a catalystmaterial (e.g., iron, nickel, cobalt, or alloys thereof) has been atleast partially depleted from a surface or volume of the polycrystallinediamond using, for example, a leaching process. A cemented carbidesubstrate (e.g., cobalt cemented, nickel cemented, cemented using alloysof cobalt, or cemented using alloys of nickel) may comprise any suitablecarbide, such as tungsten carbide, tantalum carbide, vanadium carbide,niobium carbide, chromium carbide, titanium carbide, or combinations ofthe foregoing carbides.

In at least one embodiment, the superhard material includes one or morepolycrystalline diamond compacts (PDCs). For instance, the substrate maycomprise cobalt-cemented tungsten carbide and the layer of superhardmaterial may include polycrystalline diamond. Such structures may befabricated by subjecting diamond particles, placed on or proximate to acobalt-cemented tungsten carbide substrate, to ahigh-pressure/high-temperature (HPHT) sintering process. The diamondparticles with the cobalt-cemented tungsten carbide substrate may beHPHT sintered at a temperature of at least about 1000° Celsius (e.g.,about 1100° C. to about 1600° C.) and a pressure of at least about 4 GPa(e.g., about 5 GPa to about 9 GPa) for a time sufficient to consolidateand form a coherent mass of bonded diamond grains. In such a process,the cobalt from the cobalt-cemented tungsten carbide substrate sweepsinto interstitial regions between the diamond particles to catalyzegrowth of diamond between the diamond particles. More particularly,following HPHT processing, the superhard material may comprise a matrixof diamond grains that are bonded with each other via diamond-to-diamondbonding (e.g., sp³ bonding), and the interstitial regions between thediamond grains may be at least partially occupied by cobalt or anothercatalyst, thereby creating a network of diamond grains with interposedcobalt or other catalyst, otherwise known as polycrystalline diamond(PCD).

In some embodiments, the catalyst used for forming the PCD superhardmaterial may be a metal-solvent catalyst, such as cobalt, nickel, iron,or alloys thereof. A thermal stability of such PCD superhard materialmay be improved by leaching the metal-solvent catalyst from of the PCD.Leaching may be performed in a suitable acid, such as aqua regia, nitricacid, hydrofluoric acid, or combination thereof, so that the leach PCDsuperhard material is substantially free of metal-solvent catalyst.Furthermore, the PCD superhard material may be entirely or partially.Generally, a maximum leach depth may be greater than 250 μm. Forexample, the maximum leach depth may be greater than 300 μm to about 425μm, greater than 350 μm to about 400 μm, greater than 350 μm to about375 μm, about 375 μm to about 400 μm, or about 500 μm to about 650 μm.

The superhard material comprising the PCD also may allow operation ofvarious components of the injection mold without lubricants. Thus,incorporating superhard material into injection mold components canavoid contamination of molded parts with lubricants, which, otherwise,may be required for proper operation of the injection mold in order topreserve the life of the injection mold components. In other words,incorporating PCD superhard material into the injection mold componentsmay replace lubricants and may maintain the life and usefulness of theinjection mold components. Lubricant-free operation may be particularlyadvantageous in molding medical products and/or components thereof (aswell as other clean products and components), which may have morerigorous requirements of environment cleanliness than other moldedproducts.

In one or more embodiments, the substrate may be omitted, and theinjection mold components may include one or more layers of superhardmaterials such as cemented tungsten carbide or polycrystalline diamond.Also, the layer of superhard material (e.g., diamond) may be deposited,using chemical vapor deposition (CVD), physical vapor deposition,plasma-assisted chemical vapor deposition, or other depositiontechniques. Example methods for depositing a superhard material aredescribed in U.S. Pat. No. 7,134,868, the disclosure of which isincorporated by reference herein in its entirety.

The layer of superhard material may exhibit a substantially uniformthickness (i.e., with substantially uniform thickness) or a non-uniformthickness. Additionally or alternatively, the layer of superhardmaterial may be continuous/contiguous or may be interrupted or formedfrom multiple segments. Furthermore, in some embodiments, a thickness ofthe layer of superhard material that forms a wear-resistant surface maybe in the range of about 0.010 inches to about 0.200 inches.Additionally or alternatively, the thickness of the layer of superhardmaterial may be in the range from about 0.020 inches to about 0.120inches, about 0.040 inches to about 0.100 inches, and about 0.060 inchesto about 0.090 inches. Moreover, the thickness of the superhard layermay be greater than about 0.200 inches.

In some embodiments, the superhard material may form more than onewear-resistant surface on a particular injection mold component. Forexample, as further described below, the superhard material may form twowear-resistant surfaces disposed at approximately 90° with respect toeach other. Similarly, the superhard material may have one or morebonding surfaces. Furthermore, the boding surfaces also may becontinuous or interrupted; for example, an entire surface of thesuperhard material may be bonded to the substrate or only a portionthereof. Hence, the superhard material may have more than one thicknessmeasurements, depending on the number of bonding surfaces—e.g., thesuperhard material that has two bonding surfaces, and which forms twowear-resistant surfaces, may have two or more thickness measurementsthat correspond to the thicknesses between the respective bondingsurfaces and a point on each of the wear-resistant surfaces.

The wear-resistant surface, formed by the superhard material, may have areduced amount of wear from operation of the injection mold 120, ascompared to a surface that is not formed from superhard material. Insome embodiments, the wear-resistant surface may at least in part for asurface of an injection mold component that contacts the molten moldingmaterial injected into the injection mold 120. For example, suchinjection mold component may be the sprue bushing 150, as illustrated inFIGS. 3A-3C. The sprue bushing 150 may include a through-hole 151,defined by inner wear-resistant surface 151 wr, which may allow themolten molding material to be injected from the injection moldingmachine 110 into the injection mold 120. The sprue bushing 150 also mayhave a minor diameter 152, a major diameter 153, and a shoulder 154,which may be formed between the minor and major diameters 152, 153. Oneor more of the minor diameter 152, the major diameter 153, or theshoulder 154 may assist with locating the sprue bushing 150 in theinjection mold 120.

The sprue bushing 150 also may include a seal-off 155, which may have asubstantially hemispherical shape. Hence, the injection nozzle 117 ofthe injection molding machine 110 may press against the seal-off 155, tocreate a sealed pathway for the molten molding material, from theinjection system 114 into the injection mold 120. As the material passesthrough the through-hole 151 of the sprue bushing 150, thewear-resistant surface 151 wr may provide an improved durability andwear resistance to the molten molding material, as compared to othermaterials. Similarly, repeated contact between the seal-off 155 and theinjection nozzle 117 may wear or damage the surface of the seal-off 155.

In one or more embodiments, the surface that defines the through-hole151 may be at least partially formed by a wear-resistant surface 151 wr.In particular, a superhard material 150 sm may form the wear-resistantsurface 151 wr. Furthermore, the wear-resistant surface 151 wr may spanor cover only a portion of the through-hole 151 (FIG. 3A). In someembodiments, the superhard material 150 sm that forms the wear-resistantsurface 151 wr may be disposed on an insert, which may be press-fittedinto the sprue bushing 150. Alternatively, the superhard material 150 smmay be bonded to the sprue bushing 150 directly or through thesubstrate, as described above.

In at least one embodiment, the wear-resistant surface 151 wr may spanor cover the entire through-hole 151 (FIGS. 3B and 3C). Thus, in someembodiments, the wear-resistant surface 151 wr may reduce wear(resulting from flow of molten molding material through the through-hole151) on part of the through-hole 151 of the sprue bushing 150 (FIG. 3A).Alternatively, in other embodiments, the wear-resistant surface 151 wrmay reduce such wear along the entire surface of the through-hole 151(FIGS. 3B and 3C).

Additionally or alternatively, the sprue bushing 150 also may have awear-resistant surface 155 wr disposed along the seal-off 155. Thewear-resistant surface 155 wr may reduce the amount of wear associatedwith repeated contacts of the injection nozzle 117 with the seal-off155. Accordingly, the wear-resistant surface 155 wr may extend life ofthe sprue bushing 150. In some embodiments, at least a portion of theinjection nozzle 117 may comprise superhard material.

The wear-resistant surface 155 wr may cover the entire seal-off 155. Inother embodiments, the wear-resistant surface 155 wr may cover only aportion of the seal-off 155. Moreover, the same superhard material 150sm that may form the wear-resistant surface 151 wr may also form thewear-resistant surface wear-resistant surface 155 wr. Alternatively,different separate bodies of superhard material may form thewear-resistant surfaces 151 wr and 155 wr. Also, as described above, thesuperhard material 150 sm may have varied and varying thicknesses.Furthermore, the superhard material 150 sm also may cover a top of thesprue bushing 150; in other words, the superhard material 150 sm mayextend to the major diameter 153 of the sprue bushing 150 (FIG. 3C).

In some embodiments, as illustrated in FIG. 3D, in lieu of or inaddition to a sprue bushing, the manufacturer may use a hot runnersystem 180, which may include a runner manifold 190 and one or more tipinserts 200. The molten molding material may enter the hot runner system180 through the sprue bushing. In some embodiments, the sprue bushingmay incorporate one or more heating elements and may also include one ormore wear-resistant surfaces, as described above. Alternatively, theinjection nozzle 117 may seal off against the runner manifold 190 of thehot runner system 180. Accordingly, the molten molding material from theinjection molding machine 110 may directly enter the runner manifold 190of the hot runner system 180 through the injection nozzle 117.Generally, one or more embodiments may include one or more of theinjection nozzles 117, runner manifolds 190, and tips inserts 200comprising a superhard material. More particularly, any surface (or aportion thereof) of the injection nozzle injection nozzles 117, runnermanifolds 190, and tips inserts 200 that contacts molten moldingmaterial may comprise a superhard material.

The hot runner system 180 may have one or more heater elements (notshown), which may help maintain the molding material in at leastpartially molten state within the hot runner system 180. Similarly, thetip inserts 200 also may include heating elements 201 that may keep themolding material in at least partially molten state within the tipinserts 200. The tip inserts 200 also may include an opening 202, whichmay allow the molten molding material to flow into the molding volume131 (FIG. 1). In other words, the opening 202 may provide a channel forthe molten molding material to flow from the runner manifold 190 of thehot runner system 180 into the molding volume 131, defined by one ormore molding elements 140 (FIG. 1).

In some embodiments, the opening 202 may be at least partially definedby a wear-resistant surface 202 wr. As described above, a superhardmaterial 200 sm may form the wear-resistant surface 202 wr. Furthermore,the wear-resistant surface 202 wr may span an entire length of theopening 202 or may only partially cover the surface of the opening 202.For example, the wear-resistant surface 202 wr may be disposed proximateto a connection point between the tip insert 200 and runner manifold 190(i.e., proximate to the point where the molten molding material from therunner manifold 190 enters the tip insert 200). Alternatively, thewear-resistant surface 202 wr may be disposed proximate a material exitpoint of the tip inserts 200 (i.e., proximate to the point where thematerial exits the tip insert 200 and enters the molding elements 140.

Additionally, in at least one embodiment, the tip inserts 200 also mayhave an outer portion 203 that includes one or more wear-resistantsurfaces 203 wr. For instance, the wear-resistant surface 203 wr may bedisposed proximate to an end (i.e., to the exit point) of the tip insert200. Moreover, the superhard material 200 sm that forms thewear-resistant surface 202 wr also may form the wear-resistant surfaces203 wr. As described above, the superhard material 200 sm that forms thewear-resistant surface 202 wr and/or wear-resistant surfaces 203 wr maybe bonded to a substrate that is bonded to the tip inserts 200, may bedeposited onto a surface of the tip inserts 200, and/or may form part ofan insert that is bonded or mechanically secured to one or more of thetip inserts 200.

In some instances, the part 130 (FIG. 2) molded in the injection mold120 may be direct-gated—i.e., a runner or the sprue bushing 150 mayprovide a direct pathway for the molten molding material into themolding volume 131. Alternatively, the molding elements 140 mayincorporate a tunnel gate 210, illustrated in FIG. 3E. Hence, a runner212 may connect with the tunnel gate 210 and channel the moldingmaterial into the molding volume 131 (FIG. 1). As described above, flowof the molten molding material may wear the surfaces of the 210 and/orrunner 212. Furthermore, as the injection mold 120 opens and/or as thepart 130 is ejected from the molding element 140 a or molding element140 b, the molding material in the tunnel gate 210 may be sheared off byan edge 211 of the tunnel gate 210. Thus, repetitive shearing of themolding material by the edge 211 of the tunnel gate 210 may wear, dull,and/or damage the edge 211, which may result in subnormal damage to thefinal part 130.

In at least one embodiment, the surface of the tunnel gate 210 mayinclude a wear-resistant surface 210 wr, which may be formed by asuperhard material 210 sm. The wear-resistant surface 210 wr may coverthe entire surface of the tunnel gate 210 or only a portion thereof. Insome embodiments, the edge 211 of the tunnel gate 210 also may comprisesuperhard material. Moreover, the superhard material 210 sm materialthat forms the wear-resistant surface 210 wr, also may form the edge 211of the tunnel gate 210.

Similar to the above-described superhard material, the superhardmaterial 210 sm forming the wear-resistant surface 210 wr and/or theedge 211 of the tunnel gate 210 may be bonded to a substrate that isbonded to the injection mold component (e.g., to an injection mold plateand/or to one of the molding elements 140). The superhard material 210sm also may be bonded directly to the injection mold component.Alternatively, the tunnel gate 210, at least partially, may be formed bya gate insert. Accordingly, the gate insert may incorporate thesuperhard material. In particular, the gate insert may comprise asubstrate to which a superhard material may be bonded; the gate insertalso may comprise steel or other metallic material to which thesubstrate with the superhard material 210 sm may be bonded; or the gateinsert may comprise steel or other metallic material and a bondedsuperhard material 210 sm.

In one or more embodiments, the injection mold 120 may include injectionmold components that have surfaces in contact with other injection moldcomponents (e.g., sliding surfaces that incorporate one or morewear-resistant surface formed by superhard material). For example, asillustrated in FIGS. 4A and 4B, the locating ring 160 (FIG. 2) mayinclude a locating inside diameter 161 that may fit over the majordiameter 153 of the sprue bushing 150. Accordingly, the locating ring160 may be aligned with the sprue bushing 150. Hence, the locating ring160 may be used to align the injection mold 120 within the injectionmolding machine 110, such that the injection nozzle 117 of the injectionmolding machine 110 may substantially align with the sprue bushing 150.

In particular, in one embodiment, the locating ring 160 may have anoutside diameter 163 that may fit into an opening of substantially thesame diameter in the front platen 111 of the injection molding machine110. Thus, a peripheral surface 162 of the locating ring 160 may contactthe surface (or a portion thereof) of the corresponding opening in thefront platen 111 of the injection molding machine 110. In someembodiments, the surface defining the peripheral surface 162 may beformed as or may incorporate a wear-resistant surface 163 wr, which maybe formed by superhard material 160 sm. Accordingly, the wear-resistantsurface 163 wr may have less wear and or deterioration from repeatedcontact with the corresponding opening in the front platen 111 (ascompared with a steel surface forming the outside diameter 163).

Additionally, the surface of the locating inside diameter 161 of thelocating ring 160 may contact the surface of the sprue bushing 150 thatdefines the major diameter 153. In some embodiments, the surface of thelocating inside diameter 161 may be formed as or may incorporate awear-resistant surface 161 wr, which may be formed by one or more layersof superhard material 160 sm. Accordingly, the wear-resistant surface161 wr may exhibit reduced wear or deterioration. It should be notedthat the same superhard material 160 sm may form the wear-resistantsurface 161 wr and wear-resistant surface 163 wr.

In some instances, a surface of an injection mold component (slidingsurface) may have relative sliding motion in contact with a surface ofanother injection mold component (stationary surface). In other words,the surface of a first injection mold component may slide in contactwith the surface of a second injection mold component (one or bothsurfaces may be moving during such sliding motion). For example, asdescribed above, the ejector pins 170 may be moved by the ejector plates122 d toward the front platen 111 of the injection molding machine 110,thereby ejecting the part 130 out of the injection mold 120. As theejector pins 170 move, the outside surface of the ejector pins 170(e.g., surface of the outside diameter of the ejector pins 170) mayslide or contact with the surface of corresponding openings in themolding elements 140 (e.g., in the molding element 140 b).

The contact between the opening and the ejector pins 170 may wear theejector pins 170 and/or the openings in the molding elements 140. Suchwear may result in flashing—i.e., molten molding material flowingbetween the surfaces of the ejector pins 170 and the correspondingopenings in the molding elements 140. For instance, as illustrated inFIGS. 2, 5A-5E, the molding elements 140 may incorporate an ejectorsleeve 220 (e.g., ejector sleeves 220 a, 220 b shown in FIG. 2), whichmay have one or more wear-resistant surfaces or surface segments. Suchejector sleeve 220 may be secured in one or more of the molding elements140 (e.g., in the molding element 140 b) and may, in part, form one ormore surfaces of the molding elements 140 that at least in part definesthe molding volume 131 (FIG. 1).

The ejector pins 170 may pass through an opening 221 of the ejectorsleeve 220 and eject the part 130. Alternatively, the ejector sleeve 220may be secured to the ejector plates 122 d and the opening 221 may fitaround a core pin (e.g., the core pin may be secured in the ejectorhousing 122 c). Accordingly, in some embodiments, such ejector sleeve220 also may, at least in part, move toward the front platen 111 of theinjection molding machine 110 to eject the part 130. In additional oralternative embodiments, the ejector pin 170 also may include asuperhard material 170 sm. For example, a tip of the ejector pin 170 mayincorporate superhard material 170 sm, which may form a wear-resistantsurface 170 wr.

In one or more embodiments, the opening 221 may include a fitted portion222 and a relieved portion 223. The fitted portion 222 may have a closefit with the ejector pins 170 or with the core pin, as applicable. Forinstance, the ejector pin 170 may be a cylindrical pin. Hence, theopening 221 may have a substantially cylindrical shape. Furthermore,ejector sleeve 220 may have a clearance between the internal diameter ofthe opening 221 and the outside diameter of the ejector pin 170 in therange of about 0.01 mm to about 0.15 mm. The relieve portion 223 of theopening 221 may have a clearance that is greater than 0.15 mm betweenthe internal diameter of the opening 221 and the outside diameter of theejector pin 170.

Whether stationary with respect to the ejector pins 170 (e.g., securedto the molding element 140 b) or movable with respect to a core pin(e.g., secured in the ejector plates 122 d), the ejector sleeve 220 mayinclude a wear-resistant surface 221 wr, which may be formed by asuperhard material 220 sm. The wear-resistant surface 221 wr may extendalong and cover the entire fitted portion 222 or a part of the fittedportion 222 of the opening 221. The wear-resistant surface 221 wr alsomay cover the entire relieved portion 223 or a part of the relievedportion 223 of the opening 221.

Furthermore, the superhard material 220 sm that forms the wear-resistantsurface 221 wr may have various thicknesses, as described above. Forexample, the superhard material 220 sm may have a thickness that is lessthan the distance from the wear-resistant surface 221 wr to an outerdimension of the ejector sleeve 220 (e.g., a thickness defined betweenthe inside diameter of the opening 221 and an outside diameter 225 ofthe ejector sleeve 220). The superhard material 220 sm may be bonded tothe ejector sleeve 220 in the same manner as described above inconnection with other injection mold components.

Additionally, as described above, a portion of the ejector sleeve 220may form part of one or more molding elements 140. In particular, afront face 224 of the ejector sleeve 220 may form part of the moldingelement 140 b, which may contact at least a portion of the part 130(FIG. 2). Thus, the front face 224 may experience wear caused by theflow of molten molding material in contact with the front face 224.Accordingly, the ejector sleeve 220 also may include a wear-resistantsurface 224 wr. The same superhard material 220 sm that may form thewear-resistant surface 221 wr, also may form the wear-resistant surface224 wr. The wear-resistant surface 224 wr may cover all or a portion ofthe front face 224 of the ejector sleeve 220 and/or ejector pin 170.

Additionally, as described above, thickness of the superhard material220 sm may vary, at least in part, based on the direction of themeasurement. For instance, the thickness of the same superhard material220 sm may be measured from the wear-resistant surface 221 wr as well asfrom wear-resistant surface 224 wr. Moreover, thickness of the superhardmaterial 220 sm may be measured only from one of the wear-resistantsurfaces 221 wr, 224 wr. More specifically, thickness of the superhardmaterial 220 sm (as measured from the wear-resistant surface 224 wr) maybe such as to cover part of the fitted portion 222 of the opening 221(FIG. 5B). Alternatively, thickness of the superhard material 220 sm maybe such as to cover all of the fitted portion 222 and part of therelieved portion 223 of the opening 221 (FIG. 5E).

As described above, the ejector sleeve 220, such as the ejector sleeve220 b (FIG. 2) may move with respect to the core pin. In addition tocontact that may occur between the ejector sleeve 220 and the core pin,the outside diameter 225 of the ejector sleeve 220 also may slide incontact with one or more molding elements 140 (e.g., within an openingof the molding element 140 b). Accordingly, the surface formed by theoutside diameter 225 of the ejector sleeve 220 may experience wearassociated with such sliding. In at least one embodiment, awear-resistant surface 225 wr, which may cover all or part of thesurface formed by the outside diameter 225 of the ejector sleeve 220,may reduce such wear (FIGS. 5B and 5E). Furthermore, the wear-resistantsurface 225 wr may be formed by the same body superhard material 220 smthat may form the wear-resistant surface 221 wr and/or wear-resistantsurface 224 wr.

As described above, in some instances, the molding elements 140 may formor may have undercutting portions, such that the undercut must berelieved in order to eject the part 130 from the injection mold 120. Forexample, as illustrated in FIGS. 6A-6G, the injection mold 120 mayinclude an undercut relief system 230. In at least one embodiment, theundercut relief system 230 may include a slide body 240 and a heel lock250. The slide body 240 may secure one or more of the molding elements140 (e.g., a core 140 d).

The core 140 d may form an undercutting portion of the part 130. Forexample, the core 140 d may form a hole or a ledge in the part 130.Before ejecting the part 130, the slide body 240 may move the core 140 dout of the formed hole, thereby allowing the part 130 to be ejected.While the injection mold 120 is in the closed position, an angularportion 251 of the heel lock 250 may contact a corresponding angularportion 241 of the slide body 240, which may aid in maintaining theslide body 240 in a desired position.

Accordingly, to relieve or release the undercutting portion, such as thecore 140 d, when the injection mold 120 opens, an angle pin 260 mayforce the slide body 240 to move away from the part 130 (before the part130 is ejected from the injection mold 120). More specifically, as theinjection mold 120 opens, the moving portion 122 (which may include thesecond plate 122 a and the support plate 122 b) move away from thenonmoving portion 121 (which may include the first plate 121 a and thetop clamping plate 121 b). The part 130 and the slide body 240 mayremain on the moving portion 122; the slide body 240 may be restrictedfrom movement away from the moving portion 122 by one or more gibs (notshown; see FIG. 6B-6G), which may guide the slide body 240. The slidebody 240 also may have a single degree of freedom of motion, to slideaway from the part 130 (e.g., along the second plate 122 a). Thus, asthe slide body 240 moves away from the nonmoving portion 121, whichsecures the angle pin 260. Hence, as the slide body 240 moves withrespect to the angle pin 260, the slide body 240 is forced to slide awayfrom the part 130.

In at least one embodiment, the angular portion 241 of the slide body240 may have a wear-resistant surface that covers the entire or a partof the angular portion 241. For example, a superhard material 240 sm, asdescribed above, may form all or part of the surface of the angularportion 241. Accordingly, the surface of the angular portion 241 mayhave reduced wear (compared with another material, such as steel) fromcontact with the angular portion 251.

Additionally or alternatively, the heel lock 250 also may incorporate asuperhard material 250 sm, which may form a wear-resistant surface on atleast a part of the surface of the angular portion 251. In someembodiments, the wear-resistant surface of the angular portion 251 mayhave a lower hardness than the wear-resistant surface of the angularportion 241. Alternatively, the wear-resistant surface of the angularportion 251 may have substantially the same or higher hardness than thewear-resistant surface of the angular portion 241.

Furthermore, the angular portion 241 of the slide body 240 or theangular portion 251 of the heel lock 250 may at least partiallyincorporate a wearing surface. As used herein, the term “wearing”surface refers to a surface that comprises a material that is softerthan the superhard material of the wear-resistant surface that is incontact with the wearing surface. Suitable materials for the wearingsurface include steel, brass, bronze, copper alloys, aluminum alloys,polytetrafluoroethylene (PTFA), combinations thereof, or other suitablematerial. Accordingly, the wearing surface may aid in reducing theamount of wear experienced by the wear-resistant surface. For example,the wearing surface may comprise material that is softer than thesuperhard material that comprises the wear-resistant surface. Thus, asofter wearing surface may absorb more energy generated by friction atan interface between the wear-resistant surface and a contacting surface(e.g., the wearing surface) than by a harder contacting surface. In someembodiments, the wearing surface also may have a reduced coefficient offriction (as compare to other suitable materials). To illustrate, theangular portion 241 of the slide body 240 may include a wear-resistantsurface comprising superhard material (as described above), and theangular portion 251 may have a wearing surface, which may wear morequickly or easily than the wear-resistant surface of the angular portion241, and which may increase the life of the wear-resistant surface ofthe angular portion 241.

In some embodiments, the wearing surface may be removable andreplaceable. For example, the wearing surface may comprise an insertthat incorporates material that is softer than the wear-resistantsurface that contacts the wearing surface. Hence, once the wearingsurface has worn beyond an acceptable level, the insert comprising thewearing surface may be removed and replaced.

Furthermore, as the slide body 240 moves toward and away from the part130 (or the molding elements 140 that at least in part form the part130), the slide body 240 may be guided by one or more gibs 280 (FIGS.6B-6G). One should note that, as described above in connection with FIG.6A, the cross-sectional view in FIG. 6A shows a cross-section that doesnot pass through the gibs 280; by contrast, cross-sectional views shownin FIGS. 6B-6E show a cross-section that is orthogonal to thecross-section shown in FIG. 6A, and which passes through the gibs 280.In particular, the gibs 280 may have one or more surfaces that mayprevent the slide body 240 from lifting off from a surface upon whichthe slide body 240 slides (e.g., a slide surface 290). For instance, thegibs 280 may have one or more retaining surfaces 281 (see FIG. 6F),which may restrict lifting off of the slide body 240. The slide body 240also may have one or more shoulder surfaces 243, which may interface (orinterfere) with the retaining surfaces 281 of the gibs 280.

Additionally or alternatively, the gibs 280 may have one or moresurfaces that may control the direction of movement of the slide body240, and which may limit deviation of the slide body 240 from suchdirection. In particular, the gibs 280 may have one or more sidesurfaces 282, 283, which may contact with one or more side surfaces 244,245 of the slide body 240. Accordingly, the side surfaces 244, 245 ofthe slide body 240 may move in sliding contact with the side surfaces282, 283 of the gibs 280, thereby guiding the slide body 240 along adesired path.

In one or more embodiments, one or more of the side surfaces 244, 245may incorporate wear-resistant surfaces, which may cover the portion ofside surfaces 244, 245 positioned within the gib 280 s (e.g., FIG. 6D).It should be noted that FIG. 6D illustrates different examples ofwear-resistant surfaces on the slide body 240 and on the gibs 280, whichare shown differently on the left and the right sides of an assembly ofthe slide body 240 and gibs 280. The wear-resistant surfaces also maycover only a portion of one or more of the side surfaces 244, 245 (e.g.,FIGS. 6B, 6C, and 6E). Accordingly, the side surfaces 244, 245 thatincorporate, at least in part, the wear-resistant surfaces mayexperience reduced wear from the sliding in contact with the sidesurfaces 282 and/or 283 (as compared with a different material, such assteel). As described above, the wear-resistant surfaces incorporatedinto the side surfaces 244, 245 may be formed by a superhard material240 sm, which may be bonded to the slide body 240 through a substrate,directly, or may form part of an insert secured to the slide body 240.

Additionally or alternatively, the one or more of the side surfaces 282,283 also may incorporate one or more wear-resistant surfaces, which maycover the side surfaces 282, 283 entirely or partially. In someembodiments, the wear-resistant surfaces formed on or incorporated intothe side surfaces 282, 283 may have substantially the same hardness asthe wear-resistant surface formed on or incorporated into the sidesurfaces 244, 245. In other embodiments, the wear-resistant surfacesformed as or incorporated into the side surfaces 282, 283 may be softerthan the wear-resistant surface formed as or incorporated into the sidesurfaces 244, 245. Furthermore, the wear-resistant surfaces formed on orincorporated into the side surfaces 282, 283 also may be harder than thewear-resistant surface formed on or incorporated into the side surfaces244, 245.

Moreover, the one or more wear-resistant surfaces that form one or moreof the side surfaces 244, 245 or the side surfaces 282, 283, may becontinuous or interrupted, as illustrated in FIGS. 6B-6G. For instance,as the gibs 280 may have multiple wear-resistant surfaces 281 wr and/orside surfaces 282 wr, 283 wr that may at least partially form theretaining surfaces 281 and/or side surfaces 282, 283. In one or moreembodiments, the wear-resistant surfaces 281 wr, 282 wr, 283 wr, orcombinations thereof may comprise discrete surface segments, formed bymultiple discrete layers or bodies of superhard material. Alternatively,the wear-resistant surfaces 281 wr, 282 wr, 283 wr, or combinationsthereof may be formed by a single layer or body of superhard materialthat has variable thickness to form raised portions, forming thewear-resistant surfaces 281 wr, 282 wr, and/or 283 wr.

In one or more embodiments, one or more of the side surfaces 282, 283 ofthe gibs 280 may incorporate or may be formed as wearing surfaces, whichhave a substantially lower hardness than the wear-resistant surfaces.Thus, one or more of the side surfaces 244, 245 that may be formed as orincorporate wear-resistant surfaces may experience further reduced wear.Alternatively, the side surfaces 244, 245 of the slide body 240 may beformed as or may incorporate wearing surfaces, which may come intocontact with wear-resistant surfaces formed as or incorporated into theside surfaces 282, 283.

Additionally or alternatively, the slide body 240 may have a bottomsliding surface 246, which may slide in contact or across a top surface291 of a slide plate 290. The slide plate 290 may be incorporated intoor secured to a plate comprising the nonmoving portion 121 or movingportion 122 of the injection mold 120. The slide plate 290 also may beincorporated into or secured to one or more of the molding elements 140.

The bottom sliding surface 246 of the slide body 240 may be formed as ormay incorporate a wear-resistant surface 246 wr. Similar to thewear-resistant surfaces described above, the wear-resistant surface 246wr may be formed from a single body or multiple bodies or layers ofsuperhard material. Moreover, the bottom sliding surface 246 may becontinuous or interrupted, and the wear-resistant surface 246 wr maycover the entire bottom sliding surface 246 only a part of the bottomsliding surface 246 of the slide body 240 (FIGS. 6B-6E).

The top surface 291 of the slide plate 290 also may incorporate or maybe formed as a wear-resistant surface (formed by a superhard material290 sm). In at least one embodiment, a wear-resistant surface 291 wr maybe incorporated into or may at least partially form the top surface 291of the slide plate 290. For example, the wear-resistant surface 291 wrmay cover the entire or only a portion of the top surface 291. Forexample, the wear-resistant surface 291 wr may comprise discrete surfacesegments (FIG. 6G). Alternatively, the wear-resistant surface 291 wr maycomprise a unitary on continuous surface, which may be substantiallylevel or may have raised and/or lowered portions therein.

To move the slide body 240, in some embodiments, the injection mold 120may include the angle pin 260, which may pull the slide body 240 awayfrom the part 130 as the injection mold 120 opens (FIG. 6A). Morespecifically, the angle pin 260, which may remain stationary while themoving portion 122 moves away from the nonmoving portion 121, may guidethe slide body 240 away from the part 130, as the moving portion 122(including the slide body 240) moves away from the nonmoving portion121. Alternatively, other mechanisms may be used to move the slide body240 away from the part 130. For instance, the slide body 240 may bemoved by a cylinder (e.g., a hydraulic cylinder). Thus, as shown in FIG.6A, the slide body 240 may have the opening 242, which may accommodatethe angle pin 260 therein.

In at least one embodiment, the surface of the opening 242 and/or of theangle pin 260 may include a wear-resistant surface. For example, thewear-resistant surface may cover the entire or a part of the surface ofthe opening 242 in the slide body 240. The wear-resistant surface of theopening 242 may reduce the amount of wear experienced by the opening 242from repeated entry, exit, and/or sliding movement of the angle pin 260against the surface of the opening 242 of the slide body 240. Thewear-resistant surface of the opening 242 may be formed by a superhardmaterial 240 sm, which may be bonded to a substrate (such substrate mayin turn be bonded to the slide body 240), to the slide body 240directly, or may comprise an insert that is secured to the slide body240.

Additionally, the undercut relief system 230 also may include a slideretainer 270, which may secure the slide body 240 (e.g., when theinjection mold 120 is in the open position). For example, as illustratedin FIGS. 7A and 7B, the slide retainer 270 may include a slide plate271, and a retention ball 272 and a spring 274 (i.e., a spring-loadedretention ball 272). As the slide body 240 moves away from the part 130(or the corresponding molding elements 140 forming at least a portion ofthe part 130), the slide plate 271 moves past the spring loadedretention ball 272. Once the spring loaded retention ball 272 reaches adetent 275 on the slide plate 271, the retention ball 272 may maintainthe slide plate 271 (and consequently the slide body 240) in a fixedposition.

In some instances, movement of the retention ball 272 across (and incontact with) a bottom surface of the slide plate 271 may wear thebottom surface 273 of the slide plate 271. In at least one embodiment,the bottom surface 273 of the slide plate 271 may include or may beformed by a wear-resistant surface formed by superhard material 270 sm.Furthermore, the wear-resistant surface may cover (or form) the entireor only a part of the bottom surface 273 of the slide plate 271, asshown in FIG. 7A. Also, superhard material 270 sm, which may form one ormore wear-resistant surfaces, may be continuous across the entire bottomsurface 273 of the slide plate 271 or may be interrupted. Moreover, asshown in FIG. 7B, superhard material 270 sm may comprise an insert,which may be secured to the slide body 240 (e.g., with mechanicalfasteners such as screws or using bonding techniques, such as welding,brazing, etc.). In some embodiments, the insert may comprise thesuperhard material 270 sm bonded to a substrate (FIG. 7B).Alternatively, the entire insert may comprise superhard material—i.e.,the superhard material 270 sm may be an insert secured to the slide body240.

As described above, the injection mold 120 may include one or moreinterlock pairs 280 (FIG. 2). For example, as illustrated in FIGS. 8Aand 8B, the injection mold may include one or more rectangular two-plateinterlock pairs 280 a or interlock pairs having another suitable shape.More particularly, the rectangular single side interlock pair 280 acomprise a male interlock 281 a and a female interlock 282 a. The maleinterlock 281 a may have a protrusion 283 a, which may enter andsubstantially align with a recess 284 a within the female interlock 282a. The protrusion 283 a and/or the recess 284 a may respectivelyincorporate superhard material 283 sm, 284 sm. Accordingly, theprotrusion and 283 a and the recess 284 a also may include wearresistant surfaces 283 wr, 284 wr, respectively.

As described above, the interlock pair, such as the rectangular singleside interlock pair 280 a may include small clearance on each side,between the protrusion and the recess of the respective male and femaleinterlock portions. For instance, such clearance may be in one of thefollowing ranges 0.0002 inches to 0.0005 inches 0.0005 inches to 0.001inches, and 0.001 inches to 0.005 inches. Thus, as the injection moldcloses, sides of the protrusion and the recess may slide in contact onewith the other. In particular, the wear-resistant surface 283 wr mayslide in contact with the wear-resistant surface 284 wr, as theprotrusion 283 a enters the recess 284 a.

In one or more embodiments, superhard material 283 sm and 284 sm mayform the wear-resistant surfaces 283 wr, 284 wr that may define theentire surface of the protrusion and the recess (as shown in FIGS. 8Aand 8B) or portions thereof. Additionally or alternatively, thesuperhard material 283 sm may form wear-resistant surfaces 283 wr onlyon the sides of the protrusion 283 a, as shown in FIG. 8A. Similarly,the superhard material 284 sm may form wear-resistant surface 284 wronly on the sides of the recess 284.

In additional or alternative embodiments, the superhard material 283 sm,284 sm, may form the entire protrusion 283 and recess 284, as shown inFIG. 8B. Thus, the superhard material 283 sm, 284 sm may form otherwear-resistant surfaces, in addition to the side surfaces of theprotrusion 283 and the recess 284. For instance, the part material 284sm may form a bottom wear-resistant surface 284 wr of the recess 284.Furthermore, as described above, superhard material 283 sm, 284 sm maycomprise one or more inserts, which may be secured within the maleinterlock 281 a and/or the female interlock 282 a.

In at least one embodiment, the injection mold may include a three-plateinterlock pair 280 b, as shown in FIGS. 8C and 8D, which may align threeplates of the injection mold. Accordingly, the three-plate interlockpair 280 b may include a male interlock 281 b, which may enter into twoopposing female interlocks 282 b. More specifically, the male interlock281 b may include two opposing protrusions 283 b, which may enter intorecesses 284 b of the female interlocks 282 b. Similar, as describedabove in connection with the rectangular two-plate interlock pairs 280 a(FIGS. 8A and 8B), the three-plate interlock pair 280 b may incorporatesuperhard material 283 sm, 284 sm, which may form wear-resistantsurfaces 283 wr, 284 wr of the protrusions 283 and recesses 284,respectively.

Thus, the superhard material 283 sm, 284 sm may form wear-resistantsurfaces 283 wr, 284 wr only on the respective sides of the protrusions283 and recesses 284 that contact one another (FIG. 8C). Additionally oralternatively, the superhard material 283 sm, 284 sm also may formwear-resistant surfaces 283 wr, 284 wr on other sides and/or portions ofthe male and female interlocks 281, 282. For instance, as shown in FIG.8D, the superhard material 283 sm, 284 sm may form the entire protrusion283 and/or recess 284, respectively.

The injection mold also may include tapered interlocks. For instance, asshown in FIGS. 8E and 8F, the injection mold may incorporate one or moretapered interlock pairs 280 c. More specifically, the tapered interlockpair 280 c may comprise a male interlock 281 c and a correspondingfemale interlock 282 c. The male interlock 281 c may include a taperedprotrusion 283 c that may enter a corresponding tapered recess 284 c inthe female interlock. In one or more embodiments, the tapered interlockpair 280 c may include superhard material 283 sm, 284 sm, which may formwear-resistant surfaces 283 wr, 284 wr. Additionally, the superhardmaterial 283 sm, 284 sm may form only the surfaces 283 wr, 284 wr of therespective protrusion 283 c and recess 284 c that may contact oneanother when the tapered interlock pair 280 c closes, as described above(see also FIG. 8E). The superhard material 283 sm, 284 sm also may formthe protrusion 283 c and/or the recess 284 c (FIG. 8F).

In further embodiments, the tapered interlock pair may be a cylindricaltapered interlock pair 280 d, as shown in FIGS. 8G and 8H. Similarly,the cylindrical tapered interlock pair 280 d may comprise a male andfemale interlocks 281 d, 282 d, which may have a correspondingprotrusion 283 d and recess 284 d. Also, the protrusion 283 and recess284 may include superhard material 283 sm, 284 sm, respectively, whichmay form wear-resistant surfaces 283 wr, 284 wr. As described above, thewear-resistant surfaces 283 wr, 284 wr may form only the one or moresurfaces of the respective protrusion and recess 283, 284 that maycontact one another when the cylindrical tapered interlock pair 280 dcloses (FIG. 8G). Additionally or alternatively, the superhard material283 sm, 284 sm may form the respective protrusion and/or recess 283, 284(FIG. 8H).

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments are contemplated. The various aspects andembodiments disclosed herein are for purposes of illustration and arenot intended to be limiting. Additionally, the words “including,”“having,” and variants thereof (e.g., “includes” and “has”) as usedherein, including the claims, shall be open ended and have the samemeaning as the word “comprising” and variants thereof (e.g., “comprise”and “comprises”).

We claim:
 1. A method of injection molding an article, the methodcomprising: providing a mold that includes a mold component having;providing a superhard material bonded to a cemented carbide substrate,the superhard material being formed separately from the mold component,the superhard material including a wear-resistant surface, the superhardmaterial including sintered polycrystalline diamond having a pluralityof bonded diamond grains defining interstitial regions in which at leasta portion thereof include a catalyst therein; and performing at leastone of: producing relative movement of the wear-resistant surfacerelative to one or more other mold components; or flowing moldingmaterial in contact with the wear-resistant surface.
 2. The method ofclaim 1, wherein the catalyst includes at least one of iron, nickel, orcobalt.
 3. The method of claim 1, wherein the sintered polycrystallinediamond is at least partially depleted of the catalyst.
 4. The method ofclaim 1, wherein the superhard material includes one or more segmentsdefining at least a portion of the wear-resistant surface.
 5. The methodof claim 1, wherein the wear-resistant surface exhibits a hardnessgreater than that of a wearing surface.
 6. The method of claim 1,wherein the substrate includes cemented tungsten carbide.
 7. The methodof claim 1, wherein the wear-resistant surface at least partiallydefines an internal diameter of an ejector sleeve.
 8. The method ofclaim 1, wherein the wear-resistant surface is disposed on one or moreside surfaces of a slide body.
 9. The method of claim 1, wherein thewear-resistant surface defines at least a portion of a surface of asprue bushing.
 10. The method of claim 1, further comprising bonding atleast one of the superhard material and the cemented carbide substrateto the mold component.
 11. The method of claim 1, wherein the superhardmaterial has a non-uniform thickness.
 12. The method of claim 1, whereinthe superhard material has a thickness of about 0.0010 inches to about0.200 inches.
 13. A method of injection molding an article, the methodcomprising: operably coupling a mold to a molding machine, the moldingmachine including: a first plate; a second plate; and a mold componentlocated on the first plate or on the second plate, the mold componenthaving a wear-resistant surface bonded thereto, the wear-resistantsurface comprising a superhard material bonded to a substrate, thewear-resistant surface being formed separately from the mold component,the superhard material including sintered polycrystalline diamond havinga plurality of bonded diamond grains defining interstitial regions inwhich at least a portion thereof include a catalyst therein; andperforming at least one of: producing relative movement of thewear-resistant surface relative to one or more other mold components; orflowing molding material in contact with the wear-resistant surface. 14.The method of claim 13, further comprising moving the first and secondplates away from each other or moving the first and second plates towardfrom each other.
 15. The method of claim 14, wherein producing relativemovement of the wear-resistant surface relative to one or more othermold components occurs during the movement of the first and secondplates away from each other.
 16. The method of claim 13, whereinproducing relative movement of the wear-resistant surface relative toone or more other mold components occurs when the first and secondplates are stationary relative to each other.
 17. The method of claim13, wherein the mold component is configured as an ejector sleeve, aslide body, or a sprue bushing.
 18. The method of claim 13, wherein: thesuperhard material and the substrate define an insert; and the insert isconnected to the mold component.
 19. The method of claim 18, wherein theinsert is interference fit with the mold component.
 20. The method ofclaim 18, wherein the substrate is integrated with the mold component.21. The method of claim 18, wherein the insert includes removablefasteners that secure the insert to the mold component.
 22. A moldassembly, comprising: a first mold plate; a second mold plate; and amolding element secured to one of the first or second mold plates, themolding element being formed separately from the first mold plate andthe second mold plate, the first and second mold plates configured to beabutted along respective mating surfaces thereof to form a mold cavity,the molding element including sintered polycrystalline diamond havingbonded diamond grains defining interstitial regions having a catalysttherein, the sintered polycrystalline diamond forming at least a portionof the mold cavity.
 23. The mold assembly of claim 22, wherein thesintered polycrystalline diamond is bonded to a substrate.
 24. The moldassembly of claim 22, wherein the sintered polycrystalline diamond is atleast partially depleted of the catalyst.
 25. The mold assembly of claim22, wherein the catalyst includes cobalt.
 26. The mold assembly of claim22, wherein the sintered polycrystalline diamond is at least partiallydepleted of the catalyst.